level3rc on ebay makes a great 2 piece version keeping the servo as low as possible on the axle center
Yup, that's what I used on my build, still needing to get another one for the rear as the offset servo didn't work like I need it too.
I built a Wheely King monster as well, and agree with everything said above.
First step you want to take is getting the crawler king mounts for that longer wheelbase, that short wheelbase it comes stock with definitely doesn't allow for you do to anything with it. Next I always recommend getting rid of that y-link completely and converting the truck to a true 4-link truck by using a 4 link mount that attaches to the differentials. Then lose the stock steering set up and get the Level3RC axle mounts, and the CPE servos, they are much stronger than the stock HPI servo. I tried using the HPI servo for my rear steering and it wasn't stiff enough to not turn when it wasn't on. Definitely make you some aluminum 4 links in place of the plastic ones, and I don't know if anyone mentioned it yet, but you will need to grab some T-Maxx/E-Maxx driveshafts once you extend the WB. Not only are they long enough but are also thicker than the stock WK ones and work better overall.
Take a look at the first part of this video, I go over my WK pretty well, going to have a more detailed video up here in a little bit!
[video=youtube;78YfaY9SIbA]https://www.youtube.com/watch?v=78YfaY9SIbA[/video]